From patchwork Tue Jan 26 11:46:18 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Corneliu ZUZU X-Patchwork-Id: 8120741 Return-Path: X-Original-To: patchwork-xen-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 036CBBEEE5 for ; Tue, 26 Jan 2016 11:49:12 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 300472026C for ; Tue, 26 Jan 2016 11:49:11 +0000 (UTC) Received: from lists.xen.org (lists.xenproject.org [50.57.142.19]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6569220265 for ; Tue, 26 Jan 2016 11:49:10 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xen.org) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aO253-00023X-Qa; Tue, 26 Jan 2016 11:46:41 +0000 Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aO252-00023O-Hl for xen-devel@lists.xen.org; Tue, 26 Jan 2016 11:46:40 +0000 Received: from [85.158.137.68] by server-9.bemta-3.messagelabs.com id F7/A7-03066-F9C57A65; Tue, 26 Jan 2016 11:46:39 +0000 X-Env-Sender: czuzu@bitdefender.com X-Msg-Ref: server-10.tower-31.messagelabs.com!1453808796!18146038!1 X-Originating-IP: [91.199.104.161] X-SpamReason: No, hits=0.0 required=7.0 tests= X-StarScan-Received: X-StarScan-Version: 7.35.1; banners=-,-,- X-VirusChecked: Checked Received: (qmail 25167 invoked from network); 26 Jan 2016 11:46:37 -0000 Received: from mx01.buh.bitdefender.com (HELO mx01.buh.bitdefender.com) (91.199.104.161) by server-10.tower-31.messagelabs.com with DHE-RSA-AES256-GCM-SHA384 encrypted SMTP; 26 Jan 2016 11:46:37 -0000 Comment: DomainKeys? See http://domainkeys.sourceforge.net/ DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=default; d=bitdefender.com; b=2Qxcm+txgn3D8y9ZciUNbBlJYLqQHrSFplH0aeQXkAsCxEsuQ+f/kqHqFuYl425MC8tEtrXcQI0VM1/KYHQdeF8tUDHaRmv9dEfEoWcBj26Sh7sPCISN10j2wMfGnRGxn8i4zQpuSmjt3eiRuOO3DfmRME6W7CXEcG1Wy7KPk5LShylpUPbkA/wg3eJx/PSzvhmueu6dShVSnigVYi/cejc9kF9J8n7saXuhWVHUlcHf++NsDjXBln1qjo0s2OGGknC9/j1ovFpy59pgbE8e9a9Pl7M6zQX/IeV30R06Ouo/bVl89ANh/QWnA/hQsL/tIgpl1UleZVoXp6iYjxCFcg==; h=Received:Received:Received:Received:Received:From:To:Cc:Subject:Date:Message-Id:X-Mailer:X-BitDefender-Scanner:X-BitDefender-Spam:X-BitDefender-SpamStamp:X-BitDefender-CF-Stamp; DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=bitdefender.com; h=from:to :cc:subject:date:message-id; s=default; bh=+/j/n8q7JVAWl2U64MiT+ jPpB9o=; b=rx41R1rI/qxj6+pQ6mzYGhLZBoEGXDDj2cUOVH+YRHyQUUj6Tap50 NRdqLSk+NSc8mqLWKdLowM4U75W32/NNyez+bHRz811/jVen9d1Gr3V/TIZ4v2V6 Ck1ye8MkFaMqNBeCL5KmQWVWQKdRoqGOYPg16IKT03OaztvsWItqgXEgNebYY34t CrnWReyRo2UhV+ZSb22cNfO9AJ5A8di/ya7qSwKouA2P9Qj98NeGJFxAJ+Vowx5M iiMTNuyFbLAJ20Y0bVVq6lVumHNP7qP4SwWdqVxGipLhtdcZUboxoVFbYTOw00vJ b7XX68Jux1PzknxieuK58ThrPGDt6JIvw== Received: (qmail 654 invoked from network); 26 Jan 2016 13:46:33 +0200 Received: from unknown (HELO mx-sr.buh.bitdefender.com) (10.17.80.103) by mx01.buh.bitdefender.com with AES256-GCM-SHA384 encrypted SMTP; 26 Jan 2016 13:46:33 +0200 Received: from smtp01.buh.bitdefender.com (unknown [10.17.80.75]) by mx-sr.buh.bitdefender.com (Postfix) with ESMTP id C2A3380409 for ; Tue, 26 Jan 2016 13:46:32 +0200 (EET) Received: (qmail 31392 invoked from network); 26 Jan 2016 13:46:32 +0200 Received: from unknown (HELO czuzu-dev-vm.clj.bitdefender.biz) (czuzu@bitdefender.com@172.21.6.207) by smtp01.buh.bitdefender.com with AES128-SHA256 encrypted SMTP; 26 Jan 2016 13:46:31 +0200 From: Corneliu ZUZU To: xen-devel@lists.xen.org Date: Tue, 26 Jan 2016 13:46:18 +0200 Message-Id: <1453808778-4292-1-git-send-email-czuzu@bitdefender.com> X-Mailer: git-send-email 2.5.0 X-BitDefender-Scanner: Clean, Agent: BitDefender qmail 3.1.4 on smtp01.buh.bitdefender.com, sigver: 7.64302 X-BitDefender-Spam: No (0) X-BitDefender-SpamStamp: Build: [Engines: 2.15.6.743, Dats: 413280, Stamp: 3], Multi: [Enabled, t: (0.000008, 0.001790)], BW: [Enabled, t: (0.000006,0.000001)], RBL DNSBL: [Disabled], APM: [Enabled, Score: 500, t: (0.004336), Flags: 2A917CE3; NN_NO_CONTENT_TYPE; NN_NO_LINK_NMD; NN_LEGIT_BITDEFENDER; NN_LEGIT_S_SQARE_BRACKETS; NN_LEGIT_MAILING_LIST_TO], SGN: [Enabled, t: (0.009334)], URL: [Enabled, t: (0.000006)], RTDA: [Enabled, t: (0.037940), Hit: No, Details: v2.3.2; Id: 2m1ghar.1a9km9vb7.20jqr], total: 0(775) X-BitDefender-CF-Stamp: none Cc: Stefano Stabellini , Ian Campbell Subject: [Xen-devel] [PATCH] arm: p2m.c bug-fix: hypervisor hang on __p2m_get_mem_access X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org X-Spam-Status: No, score=-4.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED, T_DKIM_INVALID, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When __p2m_get_mem_access gets called, the p2m lock is already taken by either get_page_from_gva or p2m_get_mem_access. Possible code paths: 1) -> get_page_from_gva -> p2m_mem_access_check_and_get_page -> __p2m_get_mem_access 2) -> p2m_get_mem_access -> __p2m_get_mem_access In both cases if __p2m_get_mem_access subsequently gets to call p2m_lookup (happens if !radix_tree_lookup(...)), a hypervisor hang will occur, since p2m_lookup also spin-locks on the p2m lock. This bug-fix simply replaces the p2m_lookup call from __p2m_get_mem_access with a call to __p2m_lookup. Signed-off-by: Corneliu ZUZU --- xen/arch/arm/p2m.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c index 2190908..a9157e5 100644 --- a/xen/arch/arm/p2m.c +++ b/xen/arch/arm/p2m.c @@ -490,7 +490,7 @@ static int __p2m_get_mem_access(struct domain *d, gfn_t gfn, * No setting was found in the Radix tree. Check if the * entry exists in the page-tables. */ - paddr_t maddr = p2m_lookup(d, gfn_x(gfn) << PAGE_SHIFT, NULL); + paddr_t maddr = __p2m_lookup(d, gfn_x(gfn) << PAGE_SHIFT, NULL); if ( INVALID_PADDR == maddr ) return -ESRCH;